Kinetics of oxidative cracking of n‐hexane to olefins over VOx/Ce‐Al2O3 under gas phase oxygen‐free environment. Issue 1 (15th September 2016)

• Record Type: Journal Article
• Authors: Elbadawi, AbdAlwadood H.; Khan, Muhammad Y.; Quddus, Mohammad R.; Razzak, Shaikh A.; Hossain, Mohammad M.
• Is Part Of: AIChE journal. Volume 63:Issue 1(2017)
• Page Start: 130
• Page End: 138
• Publication Date: 2016-09-15
• Subjects: oxidative cracking -- dehydrogenation -- reducibility -- acidity -- kinetics modeling -- olefins -- C–C bond fission; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; 660.28
• DOI: 10.1002/aic.15491
• Languages: English
• ISSNs: 0001-1541

Abstract

Abstract : The kinetics of oxidative cracking of n‐hexane to olefins using lattice oxygen of VOx /Ce‐Al2 O3 is investigated. The TPR/TPO analysis shows a consistent reducibility (79%) of VOx /Ce‐Al2 O3 in repeated redox cycles. The total acidity of the sample is found to be 0.54 mmol/g with 22% are strong acid sites that favors olefin selectivity. The oxidative cracking of n‐hexane in a fluidized CREC Riser simulator gives approximately 60% olefin selectivity at 30% n‐hexane conversion. A kinetic model is developed considering (1) cracking, (2) oxidative dehydrogenation (ODH), and (3) catalyst deactivations. The proposed cracking mechanism considers adsorption, C–H and C–C bond fission and desorption as elementary steps and implemented by pseudo steady state hypothesis. A Langmuir‐Hinshelwood mechanism is found to represent the ODH reactions. The developed model fits the experimental data with favorable statistical indicators. The estimated specific reaction rate constants are also found to be consistent with the product selectivity data . © 2016 American Institute of Chemical Engineers AIChE J, 63: 130–138, 2017